Starting right now on ABC's "This week" -- deadly rampage. Shots fired. Shots fired! Breaking details on the California shooting spree. The moments of terror. The urgent calls for action. We don't have to live like this! And the chilling video and manifesto left behind. Then, the pope's pilgrimage. His surprising message. We're live with Francis in the holy land. Stunning scandal. It is dishonorable, disgraceful and I will not tolerate it. The president demanding answers. Will the VA secretary keep his job? The chairman of joint chiefs weighs in. Band of brothers. On this memorial day weekend the memories that never fade. It's huge. This is what I needed. From ABC news, "This week" with George stephanopoulos begins now. Good morning. I'm Martha Raddatz. As we come on the air this morning, new details emerging about the deadly rampage near a California college. Ten minutes of terror when 22-year-old suspect Elliot Rodger opened fire, triggering a deadly chase with police. In this disturbing video, Rodger called it a day of retribution. Here's the latest. Police say there are at least ten crime scenes, seven people dead, including Rodger, son of a Hollywood director, investigators also confirming three interactions with police months before the shooting spree. So, were warning signs missed? Our experts weigh in shortly. But first, let's go to ABC's Clayton Sandell outside one of the crime scenes. Clayton? Reporter: Martha, normally I would say good morning. Right now, it is a not good morning here. Isla vista is a community in deep sorrow. Behind me, the apartment complex where Elliot Rodger lived and where police say he murdered his first three victims. A clearer picture is starting to form of 22-year-old Elliot Rodger's twisted plan, a plan that he had apparently been working on for months. Tomorrow is the day of retribution, a day in which I will have my revenge against humanity. Reporter: In this youtube video posted the day before his rampage, Rodger reveals one motive -- his rejection by women. Girls gave their affection and sex and love to other men, but never to me. Reporter: He lays out his plan to exact revenge in a rambling 140-page manifesto, he writes I found that sorority with the most beautiful girls is alpha phi sorority. I know exactly where their house is. According to authorities, Rodger drove to that sorority. And started banging on the door. Fortunately, no one opened the door. And shortly afterwards, witnesses reported seeing young women who were standing outside in the vicinity shot by the suspect. Reporter: One of ten terrifying crime scenes on this video, people divin#úkor cover when the shooting began. He fired two shots in, stopped for two seconds, before they started raining through. Reporter: Rodger's family said in the weeks before the shooting, they reached out to authorities. They sals said that he had been receiving mental health treatment. It's very, very apparent that he was severely mentally disturbed when you review that document. Reporter: Still so many unanswered questions. And a heart felt plea from one victim's father. Too many have died. We should say to ourselves, not one more. Now, of the 13 people injured in this attack, this morning, six of them remain in the hospital. Martha? Our thanks to Clayton. Here now, ABC contributor brad Garrett and senior justice correspondent Pierre Thomas. Thanks to both of you for joining us. Brad, I want to start with you, we talked about these three interactions with police where deputies actually saw him, talked to him, the last was April 30th, they went over there because his mother apparently had concerns about his safety, whether he was suicidal, had seen some videos not the one we just saw, but prior, should deputies being determined the mental health of someone like that, they basically said that he was a polite kid and left. At an alarming rate, law enforcement are being asked to be law enforcers and psychiatric social workers. When they are given a set of facts, they did an assessment by interviewing him apparently at his apartment. He was articulate, bright and lucid, typically not what they deal with day in and day out with people with mental health issues. It would appear that sort of put it to rest at that point. What else can we really do? He's acted Normal, written some inappropriate things. Pierre, let me go to you, so, what could have law enforcement done? Let me read from the manifesto that Rodger wrote. "As soon as I saw those cops, the biggest fear I had ever felt in my life overcame me, I had the striking and devastating fear that someone had somehow discovered what I was planning to do -- if they had demanded to search my room, that would have ended everything." What could law enforcement have done? They didn't have a search warrant at that point. They didn't have the predicate to search his room. We talk about connecting the dots. These things are happening so often now that police are going to have to be more proactive. One thing that could have set this in motion or stop it, was to find out he purchased weapons. You find out that the man has actually purchased weapons, that might give them the predicate to do a search. Brad, Pierre talked about the parents. They were clearly concerned. They had social workers involved, he was a 22-year-old. Very little, Martha. The problem is, when you take an individual who has no criminal history, who has sort of found his way at a college, moving on, you know as a parent, he has problems. Once he becomes an adult, his ability to acquire firearms, to have all of these very, very dark thoughts, until he takes action and law enforcement knows in advance, there's very little they can do and the parents are unfortunately sort of stuck. Pierre, quickly, I know we have seen since 1996 there have been nine instances of deadly rampages. Martha, the problem is even bigger than that, between 2008 and 2000, they were averaging five mass shootings a year. We're now averaging 15. That's a threefold increase. Is it copy-cat? It could be some copy-cats. The FBI is now training police around the country on how to respond. One thing they have decided if you get word of shooting, you have to go in and take out the suspect because there's no time, the killing will continue. The other thing they're trying to do is make their counselors available at police, behavioral scientists to consult on cases like this. Thank you very much.

This transcript has been automatically generated and may not be 100% accurate.